Attention is currently required from: Angel Pons, Arthur Heymans, Nico Huber.
Leah Rowe has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80717?usp=email )
Change subject: nb/haswell: Disable iGPU when dGPU is used ......................................................................
Patch Set 3:
(1 comment)
Patchset:
PS3: Regarding the new patch set: I made it only disable VGA decode. But I have a question: what about nvidia optimus setups? T440p and W541 thinkpads sometimes have this, and in this setup, the Intel GPU should still be used for framebuffer. I have a hunch that this patch might break the display on those machines, when the nvidia gpu is enabled, because it would do vga decode on the nvidia gpu, even though it should only be used for render offloading on those setups.
A workaround might be to make the decode-disable only apply if broadwell mrc isn't used, but that isn't a real solution. Another solution would be to additionally make vga-decode-disable (the behaviour in this patch) a toggle in option table - in other words, let the user make it so that coreboot does not disable vga decode, to work around such quirky setups.